Hadoop程序基础模板

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输入文件格式为：X,Y，表示X引用Y；
本程序目的为将引用数据进行倒排，对于每一个专利找到引用他的那些专利
import java.io.IOException;import java.util.Iterator;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.conf.Configured;import org.apache.hadoop.fs.Path;import org.apache.hadoop.io.IntWritable;import org.apache.hadoop.io.Text;import org.apache.hadoop.mapred.JobConf;import org.apache.hadoop.mapred.KeyValueTextInputFormat;import org.apache.hadoop.mapred.MapReduceBase;import org.apache.hadoop.mapred.Mapper;import org.apache.hadoop.mapred.OutputCollector;import org.apache.hadoop.mapred.Reducer;import org.apache.hadoop.mapred.Reporter;import org.apache.hadoop.mapred.TextOutputFormat;import org.apache.hadoop.mapred.FileInputFormat;import org.apache.hadoop.mapred.FileOutputFormat;import org.apache.hadoop.mapred.JobClient;import org.apache.hadoop.util.Tool;import org.apache.hadoop.util.ToolRunner;import com.google.inject.Key;import com.sun.tracing.dtrace.ArgsAttributes;public class MyJob extends Configured implements Tool {    public static class MapClass extends MapReduceBase implements Mapper<Text, Text, Text, Text>{        public void map(Text key,Text value,OutputCollector<Text, Text> output,Reporter reporter)throws IOException{            output.collect(value, key);        }    }    public static class Reduce extends MapReduceBase implements Reducer<Text, Text, Text, Text>{        public void reduce(Text key,Iterator<Text> value,OutputCollector<Text, Text> output,Reporter reporter)throws IOException{//          int sum=0;//          while(value.hasNext()){//              value.next();//              sum++;//          }//          output.collect(key, new IntWritable(sum));            String res="";            while(value.hasNext()){                if(res.length()>0)res+=",";                res+=value.next().toString();            }            output.collect(key, new Text(res));        }    }    @Override    public int run(String[] arg0) throws Exception {        // TODO Auto-generated method stub        Configuration configuration=getConf();        JobConf job=new JobConf(configuration,MyJob.class);        FileInputFormat.setInputPaths(job, new Path(arg0[0]));        FileOutputFormat.setOutputPath(job, new Path(arg0[1]));        job.setJobName("InvertedIndex");        job.setMapperClass(MapClass.class);        job.setReducerClass(Reduce.class);        job.setInputFormat(KeyValueTextInputFormat.class);        job.setOutputFormat(TextOutputFormat.class);        job.setOutputKeyClass(Text.class);        job.setOutputValueClass(Text.class);        //job.setMapOutputValueClass(Text.class);        job.set("key.value.separator.in.input.line",",");        JobClient.runJob(job);        return 0;    }    public static void main(String[] args) throws Exception{        // TODO Auto-generated method stub        //ToolRunner.run(conf, tool, args)        int res=ToolRunner.run(new Configuration(), new MyJob(), args);        System.exit(res);    }}
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